Pennsylvania's Marcellus and other shale wells produced more than 2 trillion cubic feet of natural gas in 2012, continuing a trend of production growth despite fewer drilling rigs in the field.

New production data reported by natural gas drilling companies and released by the state Department of Environmental Protection on Tuesday showed that 1.1 trillion cubic feet of gas flowed from unconventional wells in the state during the second half of 2012.

The wells produced an average of 6.2 billion cubic feet of gas per day between July and December, or enough to fulfill about 9 percent of the nation's daily natural gas demand. The U.S. consumed about 70 billion cubic feet of natural gas per day in 2012, according to the U.S. Energy Information Administration.

The state's shale gas production doubled between 2011 and 2012, even as the number of rigs drilling new wells in Pennsylvania dropped in response to lower gas prices and companies migrating to more lucrative oil shales in other states. The annual average number of drilling rigs operating in Pennsylvania declined from 110 in 2011 to 84 in 2012, according to oil field services company Baker Hughes.

In short-term energy outlook reports released last week and in January, the EIA said it expects that Marcellus Shale production will continue to grow despite relatively low natural gas prices as drilled wells are tied to an expanding network of pipelines. It also suggested that increased rig efficiency will maintain production levels, even as the number of active rigs has declined.

Energy analysts say Marcellus production is still constrained by limited pipeline infrastructure, especially in the northeast corner of the state, and those challenges will continue early this year.

Northeast Pennsylvania wells dominated the biannual production report, as they had in past reporting periods. All but three of the top 25 wells were in Susquehanna or Wyoming counties.

The top-producing well for the period, Cabot Oil & Gas Corp.'s A. Heitzenroder 3 well in Springville Twp., Susquehanna County, recorded 4.5 billion cubic feet of gas over six months.

Bradford County remained the top-producing county in the state with 285 billion cubic feet of gas coming from 609 wells.

Eleven small operators with a total of 30 unconventional wells have failed to report their data, which was due Friday, DEP spokesman Kevin Sunday said.

After reporting problems plagued the last data release in August, the state added a disclaimer to its online production database cautioning that the DEP cannot guarantee the information's accuracy, completeness or timeliness.

Contact the writer: llegere@timesshamrock.com, @shalegasTT on Twitter

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